JP5473658B2 - Air damper - Google Patents

Description

  The present invention relates to an air damper, for example, an air damper used for a shock absorber for a drawer such as an office desk or a system kitchen.

  Conventionally, as a shock absorber used in an office desk, a system kitchen or the like, a rotary damper that brakes relative movement of engagement members arranged in a drawer main body and a drawer storage portion has been proposed as a main component ( For example, see Patent Document 1).

  As the rotary damper used in this shock absorber, an oil-type rotary damper filled with oil is widely used. For this reason, the seal member deteriorates due to long-term use, the internal oil leaks out, and the inside of the drawer There was a problem that documents and valuable decorations could be soiled.

  In order to cope with such a problem, a buffer device for drawing using an air damper that uses air as a working fluid has been proposed (see, for example, Patent Document 2).

  By the way, as shown in FIG. 6A, the air damper 50 used in this shock absorber is provided with a cylindrical first seal member 52 and a tapered second seal member 53 that is widened toward the end of the piston 51. A plurality of air vents 52 a are formed outside the first seal member 52, and an air flow path 51 a is formed between the fitting portion of the first seal member 52 and the back end portion of the piston 51. .

When the air damper 50 moves the piston 51 to the closed side of the cylinder 2, as shown in FIG. 6B, the air damper 50 slides on the maximum diameter portion of the tapered second seal member 53 that is widened toward the end. The contact portion 53a more strongly contacts the inner peripheral surface 20a of the cylinder 2, and the first seal member 52 swells toward the inner peripheral surface 20a of the cylinder 2 to further prevent the air flow. Air can be gradually circulated from the plurality of air vents 52 a provided outside to the inlet side of the cylinder 2, and sufficient resistance can be applied to the piston 51.
On the other hand, when the piston 51 is moved to the opening side of the cylinder 2, as shown in FIG. 6C, the air on the inlet side of the cylinder 2 flows in through the outer periphery of the first seal member 52, The air can easily move the piston 51 with a small resistance force by flowing into the space on the closed side of the cylinder 2 from the air flow path 51a formed between the fitting portion and the back end portion of the piston 51. .

  However, the air damper 50 having the above-described configuration has a problem that the operation of the first seal member 52 is likely to be unstable, and it is difficult to obtain a reliable buffering force. There is a problem that it is necessary to form the air flow path 51a in the piston 51, and the manufacturing cost is high.

JP 2005-204790 A JP 2008-32206 A

  In view of the above-described problems of the conventional air damper, the present invention has a stable operation of the seal member, a reliable buffering force, a simple structure, a small number of parts, and an easy assembly. An object of the present invention is to provide an air damper capable of reducing the manufacturing cost.

In order to achieve the above object, an air damper according to the present invention includes a cylinder having one end closed and the other end opened, a piston having a seal member slidably in contact with an inner peripheral surface of the cylinder, and a piston extending from the piston. In an air damper composed of a rod, a seal member is connected to the cylindrical portion and a cylindrical portion formed smaller than the inner diameter of the cylinder so that a gap is formed between the piston rod side and the inner peripheral surface of the cylinder. The diameter is increased between the front and rear stages of the piston on the inner diameter side of the end on the piston rod side of the cylindrical part and the enlarged diameter part formed so as to be gradually expanded and slidably contact the inner peripheral surface of the cylinder. The outer diameter of the small-diameter step portion of the piston is formed to be larger than the outer diameter of the small-diameter step portion of the piston, and the axial length of the annular protrusion is Axial length of small diameter step Was shorter than, constituted by a tubular member having flexibility made of the annular projection loosely fitted in the cylindrical portion of the piston, when shrinking, the inner peripheral surface diameter portion of the seal member of the cylinder The expanded diameter portion of the seal member bends and the outer peripheral side of the seal member becomes the air flow path when extending so that the inner peripheral side of the seal member becomes the air flow path It is characterized by that.

In this case, a plurality of grooves extending in the axial direction can be formed on the outer peripheral surface of the cylindrical portion of the seal member.

  A plurality of ribs extending in the axial direction in sliding contact with the inner peripheral surface of the cylinder can be formed on the outer peripheral surface of the piston rod.

According to the air damper of the present invention, when contracting, the expanded diameter portion of the seal member is in sliding contact with the inner peripheral surface of the cylinder so that only the inner peripheral side of the seal member becomes an air flow path, Sufficient resistance can be given to the movement of the piston.
On the other hand, when expanding, the diameter-enlarged portion of the seal member bends so that the outer peripheral side of the seal member and the inner peripheral side of the seal member serve as an air flow path to reduce resistance to movement of the piston. be able to.
The air flow path formed on the inner peripheral side of the seal member is formed by loosely fitting an annular protrusion formed on the inner peripheral side of the cylindrical portion of the seal member to a small diameter step portion formed on the piston. Therefore, the operation of the seal member is stable and a reliable buffering force can be obtained.
Further, since the sealing member is composed of one flexible cylindrical member, the structure is simple, the number of parts is small, the assembly can be easily performed, and the manufacturing cost can be reduced.

Then, the inner diameter of the annular projection of the sealing member, as well as a larger diameter than the outer diameter of the cylindrical portion of the piston so that a gap between an outer peripheral surface of the cylindrical portion of the piston is formed, the annular By forming the length of the protrusion in the axial direction shorter than the length of the small-diameter step portion in the axial direction, an air flow path formed on the inner peripheral side of the seal member can be easily formed.

  Further, by forming a plurality of axially extending grooves on the outer peripheral surface of the cylindrical portion of the seal member, the deformation performance of the cylindrical portion is improved. A larger resistance can be applied to the movement of the piston so as to be in sliding contact with the peripheral surface.

  Further, by forming a plurality of ribs extending in the axial direction in sliding contact with the inner peripheral surface of the cylinder on the outer peripheral surface of the piston rod, the linear motion of the piston is improved and the inner peripheral surface of the cylinder of the seal member The sliding contact state can be made uniform, and the operation of the seal member can be further stabilized.

One Example of the air damper of this invention is shown, (a) is a partial sectional front view, (b) is XX sectional drawing of (a). The piston of the air damper is shown, (a) is a partially cutaway front view, and (b) is a front view showing an example of a divided structure. The sealing member attached to the piston is shown, (a) is a front view, (b) is a side view on the piston rod side, (c) is a YY sectional view of (a), and (d) is Z of (b). It is -Z sectional drawing. It is a partially cutaway front view showing a state where a seal member is attached to a piston. It is a front view of a partially cut cross section for explaining the operation of the air damper. (A) is a state where the piston is moved to the cylinder closed end side (a state when the piston is contracted), and (b) is a state where the piston is moved. The state of moving to the cylinder open end side (the state when the cylinder is extended) is shown. It is the schematic which shows the conventional air damper, (a) is a partially cutaway front view, (b) is a partially enlarged view showing a state in which the piston is moved to the cylinder closed end side, (c) is the piston It is the elements on larger scale which show the state currently moved to the cylinder open end side.

  Embodiments of an air damper according to the present invention will be described below with reference to the drawings.

  1 to 5 show an embodiment of an air damper of the present invention.

  The air damper 1 has a cylinder 2 with one end closed and the other end opened, a piston 3 with a seal member 10 slidably contacting the inner peripheral surface 20a of the cylinder 2, and a piston rod 4 extending from the piston 3. A cylindrical portion 11 having a smaller diameter than the inner diameter of the cylinder 2 so that a gap is formed between the piston rod 4 side and the inner peripheral surface 20a of the cylinder 2 from the piston rod 4 side; An enlarged diameter portion 12 formed so as to be gradually enlarged in diameter and continuously slidably contact the inner circumferential surface 20a of the cylinder 2, and a small diameter step portion 30 formed on the piston 3 formed on the inner circumferential side of the cylindrical portion 11. It is made of a cylindrical member having flexibility composed of an annular protrusion 13 that is loosely fitted.

The cylinder 2 is not particularly limited as long as one end is closed and the other end is open, but in the present embodiment, the cylinder 2 is open at both ends, The lid member 21 is configured to close one end of the cylindrical member 20.
Further, if the open end side is also configured to have a space through which the piston rod 4 passes and air flows, the lid member can be fitted.

The piston 3 moves in the cylinder 2 as the piston rod 4 moves in the axial direction of the cylinder 2, and has a smaller diameter than the inner diameter of the cylinder 2.
And the piston 3 forms the small diameter step part 30 for attaching the sealing member 10 which is slidably contacted with the internal peripheral surface 20a of the cylinder 2 in the surrounding surface.

Further, the piston 3 has a closed side (left side in the figure) of the cylinder 2 as a front stage part 31 and an open side (piston rod 4 side on the right side in the figure example) of the cylinder 2 as a rear stage part 32 with the small diameter step part 30 interposed therebetween. .
The front step portion 31, the small-diameter step portion 30, and the rear step portion 32 may have an integral structure, but in this embodiment, as shown in FIG. 2B, the seal member 10 can be easily attached. Thus, the front step portion 31 and the small diameter step portion 30 are formed separately from the rear step portion 32 side, the attachment hole 33 is opened on the end surface on the small diameter step portion 30 side, and the attachment hole 33 is formed on the end surface of the rear step portion 32. The projecting pins 34 to be fitted are formed so as to be integrated.
The tolerance between the inner diameter of the mounting hole 33 and the outer diameter of the projecting pin 34 should be in the range of an intermediate fit or an interference fit so that the piston rod 4 does not come off easily due to the axial movement of the cylinder 2. Yes.
Alternatively, a male screw may be formed on the protruding pin 34, a female screw may be formed on the mounting hole 33, and the protruding pin 34 may be screwed into the mounting hole 33.
Accordingly, the integrally formed front step portion 31 and small diameter step portion 30 are inserted into the space 10A on the inner peripheral side of the seal member 10, and the mounting hole 33 is positioned on the end surface of the seal member 10 on the annular protrusion 13 side. The sealing member 10 can be attached to the piston 3 by a simple procedure of fitting the protruding pin 34 of the rear stage portion 32 into the attachment hole 33.

The piston rod 4 provided to extend from the rear stage portion 32 of the piston 3 may be attached to the rear stage portion 32 by fixing means such as screwing or adhesion, but in this embodiment, it has an integral structure.
Further, the piston rod 4 has a length in which one end protrudes from the open end of the cylinder 2 to the outside even when the piston 3 is located at the innermost side of the cylinder 2 on the cylinder closing side. For example, the connection part 4b connected to another member can be formed.
The shape of the piston rod 4 can be a cylindrical shape slightly smaller than the inner diameter of the cylinder 2 or a prismatic shape so that the piston rod 4 can be inserted into the cylinder 2. In this embodiment, FIG. As shown, a plurality of ribs 4 a extending in the axial direction in sliding contact with the inner peripheral surface 20 a of the cylinder 2 are formed on the outer peripheral surface of the piston rod 4.
Thereby, the linear motion of the piston 3 is improved, the sliding contact state of the seal member 10 with the inner peripheral surface 20a of the cylinder 2 can be made uniform, and the operation of the seal member 10 described later can be stabilized. ing.

  As shown in FIG. 3, the seal member 10 is configured by a rubber-made cylindrical member made up of a cylindrical portion 11, an enlarged diameter portion 12, and an annular protrusion 13.

On the outer peripheral surface of the cylindrical portion 11 of the seal member 10, as shown in FIG. 3C, a plurality of axially extending grooves, in the present embodiment, four grooves 11a are formed at equal intervals. Yes.
Thereby, when the deformation | transformation performance of the cylindrical part 11 is improved and the air damper 1 is contracted, the inner peripheral surface 11b is pressed by the pressure of the air in the space 10A on the inner peripheral side of the seal member 10, and the outer periphery of the cylindrical part 11 The surface expands toward the inner peripheral surface 20 a side, and the outer peripheral surface of the cylindrical portion 11 is in sliding contact with the inner peripheral surface 20 a of the cylinder 2, so that a greater resistance force can be given to the movement of the piston 3. In addition, when the load in the direction of contracting the air damper 1 is released, the piston 3 is prevented from being pushed back in the reverse direction by the air pressure in the space 10A on the inner peripheral side of the seal member 10. ing.

The enlarged diameter portion 12 forms a sliding contact portion 12a at the tip, and the sliding contact portion 12a is formed so as to have substantially the same diameter as the inner diameter of the cylinder 2, and as the piston 3 moves, the cylinder 2 It moves so as to be in sliding contact with the inner peripheral surface 20a and restricts the flow of air in the cylinder 2.
Further, when the air damper 1 is contracted, the enlarged diameter portion 12 is configured to press the sliding contact portion 12a against the inner peripheral surface 20a of the cylinder 2 by the air pressure in the space 10A on the inner peripheral side of the seal member 10. When the peripheral surface 12b and the air damper 1 are extended, the space 10A on the inner peripheral side of the seal member 10 becomes negative pressure, so that the enlarged diameter portion 12 is bent and the air on the open end side of the cylinder 2 is sealed. 10 is provided with an outer peripheral surface 12c that smoothly circulates on the outer peripheral side.

The annular protrusion 13 loosely fitted to the small diameter step 30 formed on the piston 3 formed on the inner peripheral side of the cylindrical portion 11 has an inner diameter D1 of the annular protrusion 13 as an outer peripheral surface 30a of the small diameter step 30 of the piston 3. while a larger diameter than the outer diameter D2 of the cylindrical portion 30 of the piston 3 so that a gap is formed between the, the axial length L1 of the annular projection 13, the cylindrical portion 30 axially It is formed shorter than the length L2 in the direction, whereby the small diameter step portion 30 of the front step portion 31 of the piston 3 is formed between the outer peripheral surface 30a of the small diameter step portion 30 of the piston 3 and the inner peripheral surface 13c of the annular protrusion 13. Between the side standing surface 31a and the inner standing surface 13b of the annular protrusion 13, and the standing surface 32a on the small diameter step portion 30 side of the rear step portion 32 of the piston 3 and the outer standing surface 13a of the annular projection 13. A minute gap S1, S2 and S3 is formed between the two.
Among these gaps, the gap S2 and the gap S3 are in a state in which the standing surfaces of the annular projections 13 of the piston 3 and the seal member 10 are in contact with each other when the piston 3 moves in the cylinder 2. It is not completely sealed, and air flow from the high pressure side to the low pressure side is allowed.
In the present embodiment, the outer diameter D4 of the portion of the outer standing surface 13a of the annular protrusion 13 is formed to be smaller than the outer diameter D3 of the cylindrical portion 11, so that the air from the high pressure side to the low pressure side is formed. The amount of circulation is adjusted (increased), and thereby the magnitude of the buffering force is adjusted.
In addition, by forming a groove (not shown) through which air flows in either or both of the standing surfaces of the piston 3 and the annular protrusion 13 of the seal member 10, the amount of air flowing from the high pressure side to the low pressure side can be reduced. It can be adjusted (increased), and thereby the magnitude of the buffering force can be adjusted.

  Next, the operation of the air damper 1 will be described with reference to FIG.

When the air damper 1 is contracted, as shown in FIG. 5A, if the piston 3 is moved to the closed end side (left side in the figure) of the cylinder 2, the air in the space 2 </ b> A on the closed end side of the cylinder 2. As a result, the inner peripheral surface 12b of the enlarged diameter portion 12 is pressed, the sliding contact portion 12a of the enlarged diameter portion 12 is further strongly pressed against the inner peripheral surface 20a of the cylinder 2, and the piston 3 toward the closed end of the cylinder 2 is pressed. Provides resistance to movement.
Further, the inner circumferential surface 11 b is pressed by the pressure of the air in the inner circumferential side space 10 A of the seal member 10, the outer circumferential surface of the cylindrical portion 11 expands toward the inner circumferential surface 20 a side, and the inner circumferential surface of the cylinder 2. When the outer peripheral surface of the cylindrical portion 11 is in sliding contact with 20a, a greater resistance force is given to the movement of the piston 3, and when the load in the direction of contracting the air damper 1 is released, the seal member 10 The piston 3 is prevented from being pushed back in the reverse direction by the pressure of the air in the inner circumferential space 10A.

  The air in the space 2 </ b> A on the closed end side of the cylinder 2 on the high pressure side becomes an air flow path on the inner peripheral side of the seal member 10, specifically, the outer peripheral surface 30 a of the small diameter step portion 30 of the piston 3. Between the inner peripheral surface 13 c of the annular protrusion 13, between the standing surface 31 a on the small diameter step portion 30 side of the front step portion 31 of the piston 3 and the inner standing surface 13 b of the annular protrusion 13, and the rear step portion of the piston 3. 32, small gaps S1, S2 and S3 formed between the standing surface 32a on the small diameter step portion 30 side and the outer standing surface 13a of the annular protrusion 13 (where the gap S3 is the piston 3 and the seal). The standing surfaces 32a and 13a of the annular protrusion 13 of the member 10 are in contact with each other, but are not completely sealed, and air flow from the high pressure side to the low pressure side is allowed. And gradually flows into the space 2B on the open end side of the cylinder 2 on the low pressure side, When, given a sufficient resistance to the piston 3, it is possible to obtain a damping force.

  Next, when the air damper 1 is extended, the piston 2 is moved to the open end side (right side in the figure) of the cylinder 2 as shown in FIG. The space 10 </ b> A on the inner peripheral side of the seal member 10 connected to this becomes negative pressure, whereby the enlarged diameter portion 12 is bent, and the air in the space 2 </ b> B on the open end side of the cylinder 2 moves on the outer peripheral side of the seal member 10. (A part of the air becomes an air circulation path on the inner peripheral side of the seal member 10, specifically, the minute gaps S1, S2 and S3 (where the gap S2 is the piston 3). In addition, although the standing surfaces 31a and 13b of the annular protrusion 13 of the seal member 10 are in contact with each other, they are not completely sealed, and the flow of air from the high pressure side to the low pressure side is allowed. ))) On the closed end side of the cylinder 2 on the low pressure side. Smoothly circulated between 2A, it is possible to easily move the piston 3 with a small resistance.

  As mentioned above, although the air damper of the present invention has been described based on the embodiments thereof, the present invention is not limited to the configurations described in the above-described embodiments, and the configuration thereof may be changed as appropriate without departing from the spirit of the present invention. It is something that can be done.

  The air damper of the present invention is characterized in that the operation of the seal member is stable, a reliable buffering force is obtained, the structure is simple, the number of parts is small, the assembly can be easily performed, and the manufacturing cost can be reduced. Therefore, it can be suitably used as an air damper for a shock absorber for a drawer, and can be widely used for other shock absorber applications.

DESCRIPTION OF SYMBOLS 1 Air damper 2 Cylinder 20a Inner peripheral surface 3 Piston 30 Small diameter step part 32a Standing surface 4 Piston rod 4a Rib 10 Seal member 11 Cylindrical part 11a Groove 12 Expanded part 12a Sliding contact part 12b Inner peripheral surface 12c Outer peripheral surface 13 Annular protrusion 13a Outer standing surface D1 Inner diameter of the annular protrusion D2 Outer diameter of the small diameter step L1 Length of the annular protrusion L2 Length of the small diameter step

Claims (3)

In an air damper comprising a cylinder having one end closed and the other end open, a piston having a seal member slidably in contact with the inner peripheral surface of the cylinder, and a piston rod extending from the piston, the seal member is a piston rod. From the side, a cylindrical portion formed to have a smaller diameter than the inner diameter of the cylinder so that a gap is formed between the inner peripheral surface of the cylinder and a diameter that gradually increases from the cylindrical portion to slidably contact the inner peripheral surface of the cylinder Between the outer diameter surface of the small diameter step portion formed between the front step portion and the rear step portion of the piston on the inner peripheral side of the end portion on the piston rod side of the cylindrical portion. The outer diameter of the small-diameter step portion of the piston is made larger than the outer diameter of the piston so that a gap is formed, and the axial length of the annular protrusion is made shorter than the axial length of the small-diameter step portion of the piston . , loosely fitted to the cylindrical portion of the piston When the cylindrical member is made of a flexible cylindrical member composed of an annular protrusion and contracts, the expanded diameter portion of the seal member is in sliding contact with the inner peripheral surface of the cylinder, so that the inner peripheral side of the seal member An air damper characterized in that, when extending, a diameter-enlarged portion of the seal member is bent so that the outer peripheral side of the seal member becomes an air flow path so as to become a flow path. Wherein the outer peripheral surface of the cylindrical portion of the sealing member, according to claim 1, wherein the forming a plurality of grooves extending in the axial direction air damper. Wherein the outer peripheral surface of the piston rod, an air damper of claim 1 or 2, wherein the forming a plurality of ribs extending in the axial direction in sliding contact with the inner circumferential surface of the cylinder.

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